The drug that increases both systolic and diastolic blood pressure for prolonged period is

OSSSC Nursing Officer-2023

Pharmacology

Medium

Appeared in: OSSSC Nursing Officer-2023

Explanation

Ephedrine is a mixed-acting sympathomimetic agent, meaning it both directly stimulates adrenergic receptors (alpha and beta) and promotes the release of norepinephrine from nerve endings.
Stimulation of alpha-1 receptors causes peripheral vasoconstriction, which increases diastolic blood pressure.
Stimulation of beta-1 receptors increases heart rate and contractility, leading to a rise in cardiac output and systolic blood pressure.
Unlike catecholamines (epinephrine, dopamine), ephedrine is resistant to metabolism by key enzymes (MAO and COMT), giving it a significantly longer duration of action (30-60 minutes after injection).

Option A: Dopamine's effects are highly dose-dependent and its duration of action is very short (less than 10 minutes). It requires a continuous IV infusion to maintain its effect, so it does not provide a prolonged increase in blood pressure from a single dose.
Option C: Epinephrine has a very short duration of action (less than 5 minutes). While it potently increases systolic blood pressure, its effect on diastolic pressure is variable and can even decrease at low doses due to vasodilation in skeletal muscle (beta-2 effect).
Option D: Dobutamine primarily stimulates beta-1 receptors, increasing cardiac contractility and output. It has minimal vasoconstrictive effects, so it does not reliably increase diastolic blood pressure; diastolic pressure often remains unchanged or decreases.

Clinical Relevance

Nursing practice connection: Knowing Pharmacology of sympathomimetic drugs helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Ephedrine is commonly used by anesthesiologists to manage hypotension that can occur following spinal or epidural anesthesia, as its prolonged action provides stable blood pressure support.
Nurses administering any vasoactive drug must perform frequent monitoring of vital signs (BP and HR every 2-5 minutes initially), ECG, and urine output to titrate the drug effectively and watch for adverse effects like tachycardia or severe hypertension.
What if the patient was taking a Monoamine Oxidase Inhibitor (MAOI)? The use of ephedrine would be contraindicated. MAOIs prevent the breakdown of norepinephrine, and ephedrine causes norepinephrine release, which could lead to a life-threatening hypertensive crisis.

How to Approach the Question

First, break down the question into its key components: the drug must 1) increase systolic BP, 2) increase diastolic BP, and 3) have a prolonged action.
Evaluate each option against these three criteria.
Recall or deduce the primary receptors each drug acts on. Alpha-1 stimulation generally raises diastolic BP (vasoconstriction), while Beta-1 stimulation raises systolic BP (increased cardiac output).
Consider the metabolic pathway of each drug. Catecholamines like epinephrine and dopamine are rapidly broken down, leading to short durations. Ephedrine is not a catecholamine and is metabolized much more slowly.
Eliminate options that do not meet all three criteria. Dobutamine doesn't reliably raise DBP. Epinephrine and Dopamine do not have a prolonged action.
Conclude that Ephedrine is the only option that fits all the requirements of the question.

Concept Tested & Keywords

Concept Tested: Pharmacology of sympathomimetic drugs
Stem keywords: drug, systolic blood pressure, diastolic blood pressure, prolonged period
Lead-in keywords: increases
Negative lead-in flag: false

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E6 Pharmacology Nursing Lilley 11e Part 1 pp. 317-319, 318-320

E6 Pharmacology Katzung 16e p. 235-237